VisionSpring, a social venture, provides people glasses - which they say costs them $4-5 each. They claim that uncorrected refractive error costs the global eco

VisionSpring, a social venture, provides people glasses - which they say costs them $4-5 each. They claim that uncorrected refractive error costs the global economy an estimated $227 billion a year. https://visionspring.org/why-eyeglasses https://visionspring.org/why-eyeglasses